WARNING: Replacing the base class entirely, as opposed to applying roles to the base class, is strongly discouraged. This recipe is provided solely for reference when encountering older code that does this.

A common extension is to provide an alternate base class. One way to do that is to make a MyApp::Base and add extends 'MyApp::Base' to every class in your application. That's pretty tedious. Instead, you can create a Moose-alike module that sets the base object class to MyApp::Base for you.

Then, instead of writing use Moose you can write use MyApp::UseMyBase.

In this particular example, our base class issues some debugging output every time a new object is created, but you can think of some more interesting things to do with your own base class.

This uses the magic of Moose::Exporter. When we call Moose::Exporter->setup_import_methods( also => 'Moose' ) it builds import and unimport methods for you. The also => 'Moose' bit says that we want to export everything that Moose does.

The import method that gets created will call our init_meta method, passing it for_caller => $caller as its arguments. The $caller is set to the class that actually imported us in the first place.